1. Field of the Invention
The present invention relates to apparatuses that enhance the sense of touch for an operator using the apparatuses. The apparatuses have general utility in numerous fields where delicate procedures are undertaken, including surgery.
2. Background of the Invention
A need exists for improvement in the perception of forces by the sense of touch when performing delicate procedures. This is especially crucial when using tools in microsurgery. For example, surgeons routinely repair tiny blood vessels under a microscope that are far too delicate to be felt by the hand of the surgeon. Another key area for potential applications is ophthalmology, in which surgeons routinely pull delicate membranes off the retina that are far too flimsy to be felt by the surgeon. Providing a useful sense of touch for such applications would improve their outcome and increase the safety of the procedures.
Purely telerobotic systems such as the DA VINCI® Surgical System (Intuitive Surgical, Inc., Sunnyvale, Calif.) can provide motion-scaling, so that fine motion of the tool can be controlled by coarser motion of the operator's hand on the controls. Although force at the tool tip cannot be sensed by the operator in the current commercial DA VINCI® device, experimental systems have been tested that translate these forces into visual cues (Bethea, B., Okamura, A., Kitagawa, M., Fitton, T., Cattaneo, S., Gott, V., Baumgartner, W., Yuy, D. Application of Haptic Feedback to Robotic Surgery, J Laparoendosc, Adv. Surg. Tech. A, 14(3): 191-195, 2004) as well as into vibrotactile feedback to the operators fingers (Katherine J. Kuchenbecker, Gewirtz, J., McMahan, W., Standish, D., Martin, P., Bohren, J., Pierre P., Mendoza, J., Lee, D. VerroTouch: High-Frequency Acceleration Feedback for Telerobotic Surgery, LNCS, Volume 6191/2010, 189-196, 2010).
A different, non-telerobotic approach has been demonstrated in several experimental systems, including the Force-Reflecting Motion-Scaling System disclosed by Salcudean, et al. (Salcudean S. E., Yan J.: Motion scaling teleoperating system with force feedback suitable for microsurgery, U.S. Pat. No. 5,382,885 (1995); and Salcudean S. E., Yan J. (Towards a Force-Reflecting Motion-Scaling System for Micro-surgery, IEEE International Conference on Robotics and Automation, San Diego, Calif., 1994), and the Steady Hand Robot described by Taylor, et al. (Taylor, R., Barnes, A., Kumar, R., Gupta, P., Wang, Z., Jensen, P., Whitcomb, L., deJuan, E., Stoianovici, D., Kavoussi, L.: A Steady-Hand Robotic System for Microsurgical Augmentation, MICCAI, Lecture Notes in Computer Science, Volume 1679/1999, 1031-1041, 1999, and Fleming, I., Balicki, M., Koo, J., Iordachita, I., Mitchell, B., Handa, J., Hager, G., and Taylor, R., Cooperative Robot Assistant for Retinal Microsurgery, MICCAI 2008, Part II, LNCS 5242, pp. 543-550, 2008). These systems generate a magnified sense of touch by using a robotic arm that holds the surgical tool simultaneously with the surgeon, pushing and pulling as appropriate, to amplify the forces detected by small sensors between the handle of the tool and its tip. Because every force needs an opposing force, the robotic arm must be mounted, and because of its large size, the mounting that supports the device is substantial. Thus, the magnified forces in these systems are created between the tool handle and subsequently the floor, via the robotic arm.
To permit free motion of the tool by the surgeon, an elaborate remote-center-of-motion articulated robot arm is employed, along with a control system to keep the tool moving naturally, as if controlled just by the operator, so that the surgeon can have something approaching the degrees of freedom and ease of manipulation that he/she is accustomed to with a freely held tool. Such systems are typically fairly extensive and complex. Issues involving the limited and congested workspace common in microsurgery raise serious challenges to practical deployment.
The goal of freeing robotic surgery devices from the floor-standing/mounted robotic arm has led to hand-held systems such as the MICRON microsurgical instrument from Riviere's group, which uses piezoelectric actuators to move the tip relative to the handle, based on optical tracking of both the tip and handle. Tabars, J., MacLachlan, R., Ettensohn, C., Riviere, C.: Cell Micromanipulation with an Active Handheld Micromanipulator, 32nd Annual International Conference of the IEEE EMBS, Buenos Aires, Argentina, 2010. The primary goal of MICRON is to reduce the effects of hand tremor. It is not suited to provide a magnified sense of touch because it has no actuator between the handle of the tool and something other than the target.
Yau, et al., have developed the hand-held “MicroTactus” tool for amplifying the sense of surface textures measured at the tool tip. Yau et al. achieve this result by using an inertial actuator in the tool's handle, which can only produce changing forces whose average is zero. The device disclosed therein does not include a brace against which non-zero-average forces can be exerted by the actuator, thus limiting its utility (H. Yau, V. Hayward, R. Ellis, “A Tactile Magnification Instrument for Minimally Invasive Surgery,” MICCAI 2004, LNCS 3217, pp. 89-96.).
When the goal is to create non-zero average forces for the operator to feel, some external frame to “push against” has generally been employed. The field of haptic simulation faces the same dilemma of generating forces for the fingers to feel without anchoring the renderer to some solid base. Recent examples of more portable solutions include the “active thimble” described by Solazzi (Solazzi, et al. “Design of a Novel Finger Haptic Interface for Contact and Orientation Display,” IEEE Haptics Symposium 2010, 25-26 March, Waltham, Mass., USA). The device is entirely mounted on one hand. It attaches to the proximal part of the finger and reaches over the finger to contact the fingertip, thus generating forces between two parts of the operator's own anatomy. As described in the above-referenced publication, “[a] limit of traditional kinesthetic interfaces is the difficulty to achieve a large workspace without a detriment of dynamic performance and transparency or without increasing the mechanical complexity. A possible solution to overcome this problem is to develop portable ungrounded devices that can display forces to the user hands or fingers.”
The present invention addresses these long-standing needs by providing a haptic force magnifier that enhances the sense of touch of direct contact between a hand-held or finger-mounted device and a target that is being sensed or manipulated. The present invention achieves the enhanced sense of touch without requiring a robotic arm or any freestanding apparatus, but rather by producing forces between portions of the operator's own anatomy.